SERVER-35655 Update FCV constants throughout server code.

SERVER-35169 Bump wire protocol version for 4.2. SERVER-35752 Ensure tests that rely on FCV pass after updating FCV constants. SERVER-35163 Unblacklist tests that expect FCV version to differ between "last-stable" and "latest." SERVER-34984 Update major_version_upgrade.js to call setFCV to the latest FCV. SERVER-35656 Ensure a 4.0 mongos crashes upon attempting to connect to an FCV 4.2 cluster. SERVER-35404 Re-enable the sharding_last_stable_mongos_and_mixed_shards suite.
author: Blake Oler <blake.oler@mongodb.com> 2018-06-21 14:55:01 -0400
committer: Blake Oler <blake.oler@mongodb.com> 2018-07-02 10:50:53 -0400
commit: 53a34c4f01d6b18df4c4800df9a72b1eff07fb6a (patch)
tree: 59dcf1abafee02e14dc8d1d51c43c0965bcaf29d /src/mongo
parent: b3a542545c7367f96d57cab5e89dc389748c0e2c (diff)
download: mongo-53a34c4f01d6b18df4c4800df9a72b1eff07fb6a.tar.gz
32 files changed, 228 insertions, 304 deletions
diff --git a/src/mongo/client/dbclient_connection.cpp b/src/mongo/client/dbclient_connection.cpp
index 62bfe45726d..dbabb5ebc82 100644
--- a/src/mongo/client/dbclient_connection.cpp
+++ b/src/mongo/client/dbclient_connection.cpp
@@ -58,7 +58,6 @@
 #include "mongo/executor/remote_command_response.h"
 #include "mongo/rpc/get_status_from_command_result.h"
 #include "mongo/rpc/metadata/client_metadata.h"
-#include "mongo/s/is_mongos.h"
 #include "mongo/s/stale_exception.h"
 #include "mongo/stdx/functional.h"
 #include "mongo/stdx/memory.h"
@@ -66,7 +65,6 @@
 #include "mongo/util/assert_util.h"
 #include "mongo/util/concurrency/mutex.h"
 #include "mongo/util/debug_util.h"
-#include "mongo/util/fail_point_service.h"
 #include "mongo/util/log.h"
 #include "mongo/util/net/socket_exception.h"
 #include "mongo/util/net/socket_utils.h"
@@ -85,8 +83,6 @@ using std::string;
 
 namespace {
 
-MONGO_FAIL_POINT_DEFINE(turnOffDBClientIncompatibleWithUpgradedServerCheck);
-
 /**
  * RAII class to force usage of OP_QUERY on a connection.
  */
@@ -248,16 +244,6 @@ Status DBClientConnection::connect(const HostAndPort& serverAddress, StringData
     auto validateStatus =
         rpc::validateWireVersion(WireSpec::instance().outgoing, swProtocolSet.getValue().version);
     if (!validateStatus.isOK()) {
-        if (mongo::isMongos() && validateStatus == ErrorCodes::IncompatibleWithUpgradedServer &&
-            !MONGO_FAIL_POINT(turnOffDBClientIncompatibleWithUpgradedServerCheck)) {
-            severe() << "This mongos server must be upgraded. It is attempting to communicate with "
-                        "an upgraded cluster with which it is incompatible. Error: '"
-                     << validateStatus.toString()
-                     << "' Crashing in order to bring attention to the incompatibility, rather "
-                        "than erroring endlessly.";
-            fassertNoTrace(50709, false);
-        }
-
         warning() << "remote host has incompatible wire version: " << validateStatus;
 
         return validateStatus;
diff --git a/src/mongo/db/catalog/coll_mod.cpp b/src/mongo/db/catalog/coll_mod.cpp
index 86e955af2a8..14c1ba4f3c3 100644
--- a/src/mongo/db/catalog/coll_mod.cpp
+++ b/src/mongo/db/catalog/coll_mod.cpp
@@ -178,14 +178,14 @@ StatusWith<CollModRequest> parseCollModRequest(OperationContext* opCtx,
             // Save this to a variable to avoid reading the atomic variable multiple times.
             const auto currentFCV = serverGlobalParams.featureCompatibility.getVersion();
 
-            // If the feature compatibility version is not 4.0, and we are validating features as
-            // master, ban the use of new agg features introduced in 4.0 to prevent them from being
+            // If the feature compatibility version is not 4.2, and we are validating features as
+            // master, ban the use of new agg features introduced in 4.2 to prevent them from being
             // persisted in the catalog.
             boost::optional<ServerGlobalParams::FeatureCompatibility::Version>
                 maxFeatureCompatibilityVersion;
             if (serverGlobalParams.validateFeaturesAsMaster.load() &&
                 currentFCV !=
-                    ServerGlobalParams::FeatureCompatibility::Version::kFullyUpgradedTo40) {
+                    ServerGlobalParams::FeatureCompatibility::Version::kFullyUpgradedTo42) {
                 maxFeatureCompatibilityVersion = currentFCV;
             }
             auto statusW = coll->parseValidator(opCtx,
diff --git a/src/mongo/db/catalog/database_impl.cpp b/src/mongo/db/catalog/database_impl.cpp
index 6d5ea4b0552..5d4ed394e7c 100644
--- a/src/mongo/db/catalog/database_impl.cpp
+++ b/src/mongo/db/catalog/database_impl.cpp
@@ -1000,11 +1000,11 @@ MONGO_REGISTER_SHIM(Database::userCreateNS)
         // Save this to a variable to avoid reading the atomic variable multiple times.
         const auto currentFCV = serverGlobalParams.featureCompatibility.getVersion();
 
-        // If the feature compatibility version is not 4.0, and we are validating features as
-        // master, ban the use of new agg features introduced in 4.0 to prevent them from being
+        // If the feature compatibility version is not 4.2, and we are validating features as
+        // master, ban the use of new agg features introduced in 4.2 to prevent them from being
         // persisted in the catalog.
         if (serverGlobalParams.validateFeaturesAsMaster.load() &&
-            currentFCV != ServerGlobalParams::FeatureCompatibility::Version::kFullyUpgradedTo40) {
+            currentFCV != ServerGlobalParams::FeatureCompatibility::Version::kFullyUpgradedTo42) {
             expCtx->maxFeatureCompatibilityVersion = currentFCV;
         }
         auto statusWithMatcher =
diff --git a/src/mongo/db/commands/feature_compatibility_version.cpp b/src/mongo/db/commands/feature_compatibility_version.cpp
index c185504b6cc..740105a05e7 100644
--- a/src/mongo/db/commands/feature_compatibility_version.cpp
+++ b/src/mongo/db/commands/feature_compatibility_version.cpp
@@ -66,9 +66,9 @@ void FeatureCompatibilityVersion::setTargetUpgrade(OperationContext* opCtx) {
     // Sets both 'version' and 'targetVersion' fields.
     _runUpdateCommand(opCtx, [](auto updateMods) {
         updateMods.append(FeatureCompatibilityVersionParser::kVersionField,
-                          FeatureCompatibilityVersionParser::kVersion36);
-        updateMods.append(FeatureCompatibilityVersionParser::kTargetVersionField,
                           FeatureCompatibilityVersionParser::kVersion40);
+        updateMods.append(FeatureCompatibilityVersionParser::kTargetVersionField,
+                          FeatureCompatibilityVersionParser::kVersion42);
     });
 }
 
@@ -76,9 +76,9 @@ void FeatureCompatibilityVersion::setTargetDowngrade(OperationContext* opCtx) {
     // Sets both 'version' and 'targetVersion' fields.
     _runUpdateCommand(opCtx, [](auto updateMods) {
         updateMods.append(FeatureCompatibilityVersionParser::kVersionField,
-                          FeatureCompatibilityVersionParser::kVersion36);
+                          FeatureCompatibilityVersionParser::kVersion40);
         updateMods.append(FeatureCompatibilityVersionParser::kTargetVersionField,
-                          FeatureCompatibilityVersionParser::kVersion36);
+                          FeatureCompatibilityVersionParser::kVersion40);
     });
 }
 
@@ -121,8 +121,8 @@ void FeatureCompatibilityVersion::setIfCleanStartup(OperationContext* opCtx,
         repl::TimestampedBSONObj{
             BSON("_id" << FeatureCompatibilityVersionParser::kParameterName
                        << FeatureCompatibilityVersionParser::kVersionField
-                       << (storeUpgradeVersion ? FeatureCompatibilityVersionParser::kVersion40
-                                               : FeatureCompatibilityVersionParser::kVersion36)),
+                       << (storeUpgradeVersion ? FeatureCompatibilityVersionParser::kVersion42
+                                               : FeatureCompatibilityVersionParser::kVersion40)),
             Timestamp()},
         repl::OpTime::kUninitializedTerm));  // No timestamp or term because this write is not
                                              // replicated.
@@ -163,7 +163,7 @@ void FeatureCompatibilityVersion::onInsertOrUpdate(OperationContext* opCtx, cons
         serverGlobalParams.featureCompatibility.setVersion(newVersion);
         updateMinWireVersion();
 
-        if (newVersion != ServerGlobalParams::FeatureCompatibility::Version::kFullyDowngradedTo36) {
+        if (newVersion != ServerGlobalParams::FeatureCompatibility::Version::kFullyDowngradedTo40) {
             // Close all incoming connections from internal clients with binary versions lower than
             // ours.
             opCtx->getServiceContext()->getServiceEntryPoint()->endAllSessions(
@@ -174,9 +174,8 @@ void FeatureCompatibilityVersion::onInsertOrUpdate(OperationContext* opCtx, cons
                 .dropConnections(transport::Session::kKeepOpen);
         }
 
-        if (newVersion != ServerGlobalParams::FeatureCompatibility::Version::kFullyUpgradedTo40) {
-            // Transactions are only allowed when the featureCompatibilityVersion is 4.0, so abort
-            // any open transactions when downgrading featureCompatibilityVersion.
+        if (newVersion != ServerGlobalParams::FeatureCompatibility::Version::kFullyUpgradedTo42) {
+            // Abort all open transactions when downgrading the featureCompatibilityVersion.
             SessionKiller::Matcher matcherAllSessions(
                 KillAllSessionsByPatternSet{makeKillAllSessionsByPattern(opCtx)});
             killSessionsLocalKillTransactions(opCtx, matcherAllSessions);
@@ -188,17 +187,17 @@ void FeatureCompatibilityVersion::updateMinWireVersion() {
     WireSpec& spec = WireSpec::instance();
 
     switch (serverGlobalParams.featureCompatibility.getVersion()) {
-        case ServerGlobalParams::FeatureCompatibility::Version::kFullyUpgradedTo40:
-        case ServerGlobalParams::FeatureCompatibility::Version::kUpgradingTo40:
-        case ServerGlobalParams::FeatureCompatibility::Version::kDowngradingTo36:
+        case ServerGlobalParams::FeatureCompatibility::Version::kFullyUpgradedTo42:
+        case ServerGlobalParams::FeatureCompatibility::Version::kUpgradingTo42:
+        case ServerGlobalParams::FeatureCompatibility::Version::kDowngradingTo40:
             spec.incomingInternalClient.minWireVersion = LATEST_WIRE_VERSION;
             spec.outgoing.minWireVersion = LATEST_WIRE_VERSION;
             return;
-        case ServerGlobalParams::FeatureCompatibility::Version::kFullyDowngradedTo36:
+        case ServerGlobalParams::FeatureCompatibility::Version::kFullyDowngradedTo40:
             spec.incomingInternalClient.minWireVersion = LATEST_WIRE_VERSION - 1;
             spec.outgoing.minWireVersion = LATEST_WIRE_VERSION - 1;
             return;
-        case ServerGlobalParams::FeatureCompatibility::Version::kUnsetDefault36Behavior:
+        case ServerGlobalParams::FeatureCompatibility::Version::kUnsetDefault40Behavior:
             // getVersion() does not return this value.
             MONGO_UNREACHABLE;
     }
@@ -207,14 +206,14 @@ void FeatureCompatibilityVersion::updateMinWireVersion() {
 void FeatureCompatibilityVersion::_validateVersion(StringData version) {
     uassert(40284,
             str::stream() << "featureCompatibilityVersion must be '"
-                          << FeatureCompatibilityVersionParser::kVersion40
+                          << FeatureCompatibilityVersionParser::kVersion42
                           << "' or '"
-                          << FeatureCompatibilityVersionParser::kVersion36
+                          << FeatureCompatibilityVersionParser::kVersion40
                           << "'. See "
                           << feature_compatibility_version_documentation::kCompatibilityLink
                           << ".",
-            version == FeatureCompatibilityVersionParser::kVersion40 ||
-                version == FeatureCompatibilityVersionParser::kVersion36);
+            version == FeatureCompatibilityVersionParser::kVersion42 ||
+                version == FeatureCompatibilityVersionParser::kVersion40);
 }
 
 void FeatureCompatibilityVersion::_runUpdateCommand(OperationContext* opCtx,
@@ -267,33 +266,33 @@ public:
                               << " is not yet known.",
                 serverGlobalParams.featureCompatibility.isVersionInitialized());
         switch (serverGlobalParams.featureCompatibility.getVersion()) {
-            case ServerGlobalParams::FeatureCompatibility::Version::kFullyUpgradedTo40:
+            case ServerGlobalParams::FeatureCompatibility::Version::kFullyUpgradedTo42:
                 featureCompatibilityVersionBuilder.append(
                     FeatureCompatibilityVersionParser::kVersionField,
-                    FeatureCompatibilityVersionParser::kVersion40);
+                    FeatureCompatibilityVersionParser::kVersion42);
                 return;
-            case ServerGlobalParams::FeatureCompatibility::Version::kUpgradingTo40:
+            case ServerGlobalParams::FeatureCompatibility::Version::kUpgradingTo42:
                 featureCompatibilityVersionBuilder.append(
                     FeatureCompatibilityVersionParser::kVersionField,
-                    FeatureCompatibilityVersionParser::kVersion36);
+                    FeatureCompatibilityVersionParser::kVersion40);
                 featureCompatibilityVersionBuilder.append(
                     FeatureCompatibilityVersionParser::kTargetVersionField,
-                    FeatureCompatibilityVersionParser::kVersion40);
+                    FeatureCompatibilityVersionParser::kVersion42);
                 return;
-            case ServerGlobalParams::FeatureCompatibility::Version::kDowngradingTo36:
+            case ServerGlobalParams::FeatureCompatibility::Version::kDowngradingTo40:
                 featureCompatibilityVersionBuilder.append(
                     FeatureCompatibilityVersionParser::kVersionField,
-                    FeatureCompatibilityVersionParser::kVersion36);
+                    FeatureCompatibilityVersionParser::kVersion40);
                 featureCompatibilityVersionBuilder.append(
                     FeatureCompatibilityVersionParser::kTargetVersionField,
-                    FeatureCompatibilityVersionParser::kVersion36);
+                    FeatureCompatibilityVersionParser::kVersion40);
                 return;
-            case ServerGlobalParams::FeatureCompatibility::Version::kFullyDowngradedTo36:
+            case ServerGlobalParams::FeatureCompatibility::Version::kFullyDowngradedTo40:
                 featureCompatibilityVersionBuilder.append(
                     FeatureCompatibilityVersionParser::kVersionField,
-                    FeatureCompatibilityVersionParser::kVersion36);
+                    FeatureCompatibilityVersionParser::kVersion40);
                 return;
-            case ServerGlobalParams::FeatureCompatibility::Version::kUnsetDefault36Behavior:
+            case ServerGlobalParams::FeatureCompatibility::Version::kUnsetDefault40Behavior:
                 // getVersion() does not return this value.
                 MONGO_UNREACHABLE;
         }
diff --git a/src/mongo/db/commands/feature_compatibility_version.h b/src/mongo/db/commands/feature_compatibility_version.h
index e41530edddd..bf6ffab1dbe 100644
--- a/src/mongo/db/commands/feature_compatibility_version.h
+++ b/src/mongo/db/commands/feature_compatibility_version.h
@@ -57,21 +57,21 @@ public:
     static Lock::ResourceMutex fcvLock;
 
     /**
-     * Records intent to perform a 3.6 -> 4.0 upgrade by updating the on-disk feature
-     * compatibility version document to have 'version'=3.6, 'targetVersion'=4.0.
+     * Records intent to perform a 4.0 -> 4.2 upgrade by updating the on-disk feature
+     * compatibility version document to have 'version'=4.0, 'targetVersion'=4.2.
      * Should be called before schemas are modified.
      */
     static void setTargetUpgrade(OperationContext* opCtx);
 
     /**
-     * Records intent to perform a 4.0 -> 3.6 downgrade by updating the on-disk feature
-     * compatibility version document to have 'version'=3.6, 'targetVersion'=3.6.
+     * Records intent to perform a 4.2 -> 4.0 downgrade by updating the on-disk feature
+     * compatibility version document to have 'version'=4.0, 'targetVersion'=4.0.
      * Should be called before schemas are modified.
      */
     static void setTargetDowngrade(OperationContext* opCtx);
 
     /**
-     * Records the completion of a 3.6 <-> 4.0 upgrade or downgrade by updating the on-disk feature
+     * Records the completion of a 4.0 <-> 4.2 upgrade or downgrade by updating the on-disk feature
      * compatibility version document to have 'version'=version and unsetting the 'targetVersion'
      * field.
      * Should be called after schemas are modified.
diff --git a/src/mongo/db/commands/feature_compatibility_version_command_parser.cpp b/src/mongo/db/commands/feature_compatibility_version_command_parser.cpp
index 2e15ce22a91..65ca5652552 100644
--- a/src/mongo/db/commands/feature_compatibility_version_command_parser.cpp
+++ b/src/mongo/db/commands/feature_compatibility_version_command_parser.cpp
@@ -81,13 +81,13 @@ StatusWith<std::string> FeatureCompatibilityVersionCommandParser::extractVersion
 
     const std::string version = versionElem.String();
 
-    if (version != FeatureCompatibilityVersionParser::kVersion40 &&
-        version != FeatureCompatibilityVersionParser::kVersion36) {
+    if (version != FeatureCompatibilityVersionParser::kVersion42 &&
+        version != FeatureCompatibilityVersionParser::kVersion40) {
         return {ErrorCodes::BadValue,
                 str::stream() << "Invalid command argument. Expected '"
-                              << FeatureCompatibilityVersionParser::kVersion40
+                              << FeatureCompatibilityVersionParser::kVersion42
                               << "' or '"
-                              << FeatureCompatibilityVersionParser::kVersion36
+                              << FeatureCompatibilityVersionParser::kVersion40
                               << "', found "
                               << version
                               << " in: "
diff --git a/src/mongo/db/commands/feature_compatibility_version_parser.cpp b/src/mongo/db/commands/feature_compatibility_version_parser.cpp
index 30eeca1bf4c..49b72b0ffc7 100644
--- a/src/mongo/db/commands/feature_compatibility_version_parser.cpp
+++ b/src/mongo/db/commands/feature_compatibility_version_parser.cpp
@@ -37,10 +37,10 @@
 
 namespace mongo {
 
-constexpr StringData FeatureCompatibilityVersionParser::kVersion36;
 constexpr StringData FeatureCompatibilityVersionParser::kVersion40;
-constexpr StringData FeatureCompatibilityVersionParser::kVersionDowngradingTo36;
-constexpr StringData FeatureCompatibilityVersionParser::kVersionUpgradingTo40;
+constexpr StringData FeatureCompatibilityVersionParser::kVersion42;
+constexpr StringData FeatureCompatibilityVersionParser::kVersionDowngradingTo40;
+constexpr StringData FeatureCompatibilityVersionParser::kVersionUpgradingTo42;
 constexpr StringData FeatureCompatibilityVersionParser::kVersionUnset;
 
 constexpr StringData FeatureCompatibilityVersionParser::kParameterName;
@@ -50,7 +50,7 @@ constexpr StringData FeatureCompatibilityVersionParser::kTargetVersionField;
 StatusWith<ServerGlobalParams::FeatureCompatibility::Version>
 FeatureCompatibilityVersionParser::parse(const BSONObj& featureCompatibilityVersionDoc) {
     ServerGlobalParams::FeatureCompatibility::Version version =
-        ServerGlobalParams::FeatureCompatibility::Version::kUnsetDefault36Behavior;
+        ServerGlobalParams::FeatureCompatibility::Version::kUnsetDefault40Behavior;
     std::string versionString;
     std::string targetVersionString;
 
@@ -75,15 +75,15 @@ FeatureCompatibilityVersionParser::parse(const BSONObj& featureCompatibilityVers
                                   << ".");
             }
 
-            if (elem.String() != kVersion40 && elem.String() != kVersion36) {
+            if (elem.String() != kVersion42 && elem.String() != kVersion40) {
                 return Status(
                     ErrorCodes::BadValue,
                     str::stream() << "Invalid value for " << fieldName << ", found "
                                   << elem.String()
                                   << ", expected '"
-                                  << kVersion40
+                                  << kVersion42
                                   << "' or '"
-                                  << kVersion36
+                                  << kVersion40
                                   << "'. Contents of "
                                   << kParameterName
                                   << " document in "
@@ -115,16 +115,16 @@ FeatureCompatibilityVersionParser::parse(const BSONObj& featureCompatibilityVers
         }
     }
 
-    if (versionString == kVersion36) {
-        if (targetVersionString == kVersion40) {
-            version = ServerGlobalParams::FeatureCompatibility::Version::kUpgradingTo40;
-        } else if (targetVersionString == kVersion36) {
-            version = ServerGlobalParams::FeatureCompatibility::Version::kDowngradingTo36;
+    if (versionString == kVersion40) {
+        if (targetVersionString == kVersion42) {
+            version = ServerGlobalParams::FeatureCompatibility::Version::kUpgradingTo42;
+        } else if (targetVersionString == kVersion40) {
+            version = ServerGlobalParams::FeatureCompatibility::Version::kDowngradingTo40;
         } else {
-            version = ServerGlobalParams::FeatureCompatibility::Version::kFullyDowngradedTo36;
+            version = ServerGlobalParams::FeatureCompatibility::Version::kFullyDowngradedTo40;
         }
-    } else if (versionString == kVersion40) {
-        if (targetVersionString == kVersion40 || targetVersionString == kVersion36) {
+    } else if (versionString == kVersion42) {
+        if (targetVersionString == kVersion42 || targetVersionString == kVersion40) {
             return Status(
                 ErrorCodes::BadValue,
                 str::stream() << "Invalid state for " << kParameterName << " document in "
@@ -135,7 +135,7 @@ FeatureCompatibilityVersionParser::parse(const BSONObj& featureCompatibilityVers
                               << feature_compatibility_version_documentation::kCompatibilityLink
                               << ".");
         } else {
-            version = ServerGlobalParams::FeatureCompatibility::Version::kFullyUpgradedTo40;
+            version = ServerGlobalParams::FeatureCompatibility::Version::kFullyUpgradedTo42;
         }
     } else {
         return Status(
diff --git a/src/mongo/db/commands/feature_compatibility_version_parser.h b/src/mongo/db/commands/feature_compatibility_version_parser.h
index ac36f73556a..672a6fdc229 100644
--- a/src/mongo/db/commands/feature_compatibility_version_parser.h
+++ b/src/mongo/db/commands/feature_compatibility_version_parser.h
@@ -39,10 +39,10 @@ namespace mongo {
  */
 class FeatureCompatibilityVersionParser {
 public:
-    static constexpr StringData kVersion36 = "3.6"_sd;
     static constexpr StringData kVersion40 = "4.0"_sd;
-    static constexpr StringData kVersionDowngradingTo36 = "downgrading to 3.6"_sd;
-    static constexpr StringData kVersionUpgradingTo40 = "upgrading to 4.0"_sd;
+    static constexpr StringData kVersion42 = "4.2"_sd;
+    static constexpr StringData kVersionDowngradingTo40 = "downgrading to 4.0"_sd;
+    static constexpr StringData kVersionUpgradingTo42 = "upgrading to 4.2"_sd;
     static constexpr StringData kVersionUnset = "Unset"_sd;
 
     static constexpr StringData kParameterName = "featureCompatibilityVersion"_sd;
@@ -62,16 +62,16 @@ public:
      */
     static StringData toString(ServerGlobalParams::FeatureCompatibility::Version version) {
         switch (version) {
-            case ServerGlobalParams::FeatureCompatibility::Version::kUnsetDefault36Behavior:
+            case ServerGlobalParams::FeatureCompatibility::Version::kUnsetDefault40Behavior:
                 return kVersionUnset;
-            case ServerGlobalParams::FeatureCompatibility::Version::kFullyDowngradedTo36:
-                return kVersion36;
-            case ServerGlobalParams::FeatureCompatibility::Version::kUpgradingTo40:
-                return kVersionUpgradingTo40;
-            case ServerGlobalParams::FeatureCompatibility::Version::kDowngradingTo36:
-                return kVersionDowngradingTo36;
-            case ServerGlobalParams::FeatureCompatibility::Version::kFullyUpgradedTo40:
+            case ServerGlobalParams::FeatureCompatibility::Version::kFullyDowngradedTo40:
                 return kVersion40;
+            case ServerGlobalParams::FeatureCompatibility::Version::kUpgradingTo42:
+                return kVersionUpgradingTo42;
+            case ServerGlobalParams::FeatureCompatibility::Version::kDowngradingTo40:
+                return kVersionDowngradingTo40;
+            case ServerGlobalParams::FeatureCompatibility::Version::kFullyUpgradedTo42:
+                return kVersion42;
             default:
                 MONGO_UNREACHABLE;
         }
diff --git a/src/mongo/db/commands/set_feature_compatibility_version_command.cpp b/src/mongo/db/commands/set_feature_compatibility_version_command.cpp
index 92ef3d07a7c..e751532068b 100644
--- a/src/mongo/db/commands/set_feature_compatibility_version_command.cpp
+++ b/src/mongo/db/commands/set_feature_compatibility_version_command.cpp
@@ -57,7 +57,7 @@ namespace {
 MONGO_FAIL_POINT_DEFINE(featureCompatibilityDowngrade);
 MONGO_FAIL_POINT_DEFINE(featureCompatibilityUpgrade);
 /**
- * Sets the minimum allowed version for the cluster. If it is 3.4, then the node should not use 3.6
+ * Sets the minimum allowed version for the cluster. If it is 4.0, then the node should not use 4.2
  * features.
  *
  * Format:
@@ -85,11 +85,11 @@ public:
     std::string help() const override {
         std::stringstream h;
         h << "Set the API version exposed by this node. If set to \""
-          << FeatureCompatibilityVersionParser::kVersion36
-          << "\", then 4.0 features are disabled. If \""
           << FeatureCompatibilityVersionParser::kVersion40
-          << "\", then 4.0 features are enabled, and all nodes in the cluster must be binary "
-             "version 4.0. See "
+          << "\", then 4.2 features are disabled. If \""
+          << FeatureCompatibilityVersionParser::kVersion42
+          << "\", then 4.2 features are enabled, and all nodes in the cluster must be binary "
+             "version 4.2. See "
           << feature_compatibility_version_documentation::kCompatibilityLink << ".";
         return h.str();
     }
@@ -138,16 +138,16 @@ public:
         ServerGlobalParams::FeatureCompatibility::Version actualVersion =
             serverGlobalParams.featureCompatibility.getVersion();
 
-        if (requestedVersion == FeatureCompatibilityVersionParser::kVersion40) {
+        if (requestedVersion == FeatureCompatibilityVersionParser::kVersion42) {
             uassert(ErrorCodes::IllegalOperation,
-                    "cannot initiate featureCompatibilityVersion upgrade to 4.0 while a previous "
-                    "featureCompatibilityVersion downgrade to 3.6 has not completed. Finish "
-                    "downgrade to 3.6, then upgrade to 4.0.",
+                    "cannot initiate featureCompatibilityVersion upgrade to 4.2 while a previous "
+                    "featureCompatibilityVersion downgrade to 4.0 has not completed. Finish "
+                    "downgrade to 4.0, then upgrade to 4.2.",
                     actualVersion !=
-                        ServerGlobalParams::FeatureCompatibility::Version::kDowngradingTo36);
+                        ServerGlobalParams::FeatureCompatibility::Version::kDowngradingTo40);
 
             if (actualVersion ==
-                ServerGlobalParams::FeatureCompatibility::Version::kFullyUpgradedTo40) {
+                ServerGlobalParams::FeatureCompatibility::Version::kFullyUpgradedTo42) {
                 // Set the client's last opTime to the system last opTime so no-ops wait for
                 // writeConcern.
                 repl::ReplClientInfo::forClient(opCtx->getClient())
@@ -161,7 +161,7 @@ public:
                 // Take the global lock in S mode to create a barrier for operations taking the
                 // global IX or X locks. This ensures that either
                 //   - The global IX/X locked operation will start after the FCV change, see the
-                //     upgrading to 4.0 FCV and act accordingly.
+                //     upgrading to 4.2 FCV and act accordingly.
                 //   - The global IX/X locked operation began prior to the FCV change, is acting on
                 //     that assumption and will finish before upgrade procedures begin right after
                 //     this.
@@ -183,15 +183,15 @@ public:
             }
 
             FeatureCompatibilityVersion::unsetTargetUpgradeOrDowngrade(opCtx, requestedVersion);
-        } else if (requestedVersion == FeatureCompatibilityVersionParser::kVersion36) {
+        } else if (requestedVersion == FeatureCompatibilityVersionParser::kVersion40) {
             uassert(ErrorCodes::IllegalOperation,
-                    "cannot initiate setting featureCompatibilityVersion to 3.6 while a previous "
-                    "featureCompatibilityVersion upgrade to 4.0 has not completed.",
+                    "cannot initiate setting featureCompatibilityVersion to 4.0 while a previous "
+                    "featureCompatibilityVersion upgrade to 4.2 has not completed.",
                     actualVersion !=
-                        ServerGlobalParams::FeatureCompatibility::Version::kUpgradingTo40);
+                        ServerGlobalParams::FeatureCompatibility::Version::kUpgradingTo42);
 
             if (actualVersion ==
-                ServerGlobalParams::FeatureCompatibility::Version::kFullyDowngradedTo36) {
+                ServerGlobalParams::FeatureCompatibility::Version::kFullyDowngradedTo40) {
                 // Set the client's last opTime to the system last opTime so no-ops wait for
                 // writeConcern.
                 repl::ReplClientInfo::forClient(opCtx->getClient())
@@ -205,7 +205,7 @@ public:
                 // Take the global lock in S mode to create a barrier for operations taking the
                 // global IX or X locks. This ensures that either
                 //   - The global IX/X locked operation will start after the FCV change, see the
-                //     downgrading to 3.6 FCV and act accordingly.
+                //     downgrading to 4.0 FCV and act accordingly.
                 //   - The global IX/X locked operation began prior to the FCV change, is acting on
                 //     that assumption and will finish before downgrade procedures begin right after
                 //     this.
diff --git a/src/mongo/db/pipeline/expression.cpp b/src/mongo/db/pipeline/expression.cpp
index 5cb0122f565..200792ac734 100644
--- a/src/mongo/db/pipeline/expression.cpp
+++ b/src/mongo/db/pipeline/expression.cpp
@@ -1343,34 +1343,6 @@ intrusive_ptr<Expression> ExpressionDateFromString::parse(
         }
     }
 
-    // The 'format', 'onNull' and 'onError' options were introduced in 4.0, and should not be
-    // allowed in contexts where the maximum feature version is <= 4.0.
-    if (expCtx->maxFeatureCompatibilityVersion &&
-        *expCtx->maxFeatureCompatibilityVersion <
-            ServerGlobalParams::FeatureCompatibility::Version::kFullyUpgradedTo40) {
-        uassert(
-            ErrorCodes::QueryFeatureNotAllowed,
-            str::stream() << "\"format\" option to $dateFromString is not allowed with the current "
-                             "feature compatibility version. See "
-                          << feature_compatibility_version_documentation::kCompatibilityLink
-                          << " for more information.",
-            !formatElem);
-        uassert(
-            ErrorCodes::QueryFeatureNotAllowed,
-            str::stream() << "\"onNull\" option to $dateFromString is not allowed with the current "
-                             "feature compatibility version. See "
-                          << feature_compatibility_version_documentation::kCompatibilityLink
-                          << " for more information.",
-            !onNullElem);
-        uassert(ErrorCodes::QueryFeatureNotAllowed,
-                str::stream()
-                    << "\"onError\" option to $dateFromString is not allowed with the current "
-                       "feature compatibility version. See "
-                    << feature_compatibility_version_documentation::kCompatibilityLink
-                    << " for more information.",
-                !onErrorElem);
-    }
-
     uassert(40542, "Missing 'dateString' parameter to $dateFromString", dateStringElem);
 
     return new ExpressionDateFromString(
@@ -1691,28 +1663,6 @@ intrusive_ptr<Expression> ExpressionDateToString::parse(
         }
     }
 
-    // The 'onNull' option was introduced in 4.0, and should not be allowed in contexts where the
-    // maximum feature version is <= 4.0. Similarly, the 'format' option was made optional in 4.0,
-    // so should be required in such scenarios.
-    if (expCtx->maxFeatureCompatibilityVersion &&
-        *expCtx->maxFeatureCompatibilityVersion <
-            ServerGlobalParams::FeatureCompatibility::Version::kFullyUpgradedTo40) {
-        uassert(
-            ErrorCodes::QueryFeatureNotAllowed,
-            str::stream() << "\"onNull\" option to $dateToString is not allowed with the current "
-                             "feature compatibility version. See "
-                          << feature_compatibility_version_documentation::kCompatibilityLink
-                          << " for more information.",
-            !onNullElem);
-
-        uassert(ErrorCodes::QueryFeatureNotAllowed,
-                str::stream() << "\"format\" option to $dateToString is required with the current "
-                                 "feature compatibility version. See "
-                              << feature_compatibility_version_documentation::kCompatibilityLink
-                              << " for more information.",
-                formatElem);
-    }
-
     uassert(18628, "Missing 'date' parameter to $dateToString", !dateElem.eoo());
 
     return new ExpressionDateToString(expCtx,
diff --git a/src/mongo/db/repair_database_and_check_version.cpp b/src/mongo/db/repair_database_and_check_version.cpp
index 7eb1ad2d917..78a1e380718 100644
--- a/src/mongo/db/repair_database_and_check_version.cpp
+++ b/src/mongo/db/repair_database_and_check_version.cpp
@@ -68,8 +68,8 @@ using std::endl;
 namespace {
 
 const std::string mustDowngradeErrorMsg = str::stream()
-    << "UPGRADE PROBLEM: The data files need to be fully upgraded to version 3.6 before attempting "
-       "an upgrade to 4.0; see "
+    << "UPGRADE PROBLEM: The data files need to be fully upgraded to version 4.0 before attempting "
+       "an upgrade to 4.2; see "
     << feature_compatibility_version_documentation::kUpgradeLink << " for more details.";
 
 Status restoreMissingFeatureCompatibilityVersionDocument(OperationContext* opCtx,
@@ -104,11 +104,11 @@ Status restoreMissingFeatureCompatibilityVersionDocument(OperationContext* opCtx
                           BSON("_id" << FeatureCompatibilityVersionParser::kParameterName),
                           featureCompatibilityVersion)) {
         log() << "Re-creating featureCompatibilityVersion document that was deleted with version "
-              << FeatureCompatibilityVersionParser::kVersion36 << ".";
+              << FeatureCompatibilityVersionParser::kVersion40 << ".";
 
         BSONObj fcvObj = BSON("_id" << FeatureCompatibilityVersionParser::kParameterName
                                     << FeatureCompatibilityVersionParser::kVersionField
-                                    << FeatureCompatibilityVersionParser::kVersion36);
+                                    << FeatureCompatibilityVersionParser::kVersion40);
 
         writeConflictRetry(opCtx, "insertFCVDocument", fcvNss.ns(), [&] {
             WriteUnitOfWork wunit(opCtx);
@@ -426,14 +426,14 @@ StatusWith<bool> repairDatabasesAndCheckVersion(OperationContext* opCtx) {
                     if (!swVersion.isOK()) {
                         severe() << swVersion.getStatus();
                         // Note this error path captures all cases of an FCV document existing,
-                        // but with any value other than "3.6" or "4.0". This includes unexpected
+                        // but with any value other than "4.0" or "4.2". This includes unexpected
                         // cases with no path forward such as the FCV value not being a string.
                         return {ErrorCodes::MustDowngrade,
                                 str::stream()
                                     << "UPGRADE PROBLEM: Unable to parse the "
                                        "featureCompatibilityVersion document. The data files need "
-                                       "to be fully upgraded to version 3.6 before attempting an "
-                                       "upgrade to 4.0. If you are upgrading to 4.0, see "
+                                       "to be fully upgraded to version 4.0 before attempting an "
+                                       "upgrade to 4.2. If you are upgrading to 4.2, see "
                                     << feature_compatibility_version_documentation::kUpgradeLink
                                     << "."};
                     }
@@ -445,23 +445,23 @@ StatusWith<bool> repairDatabasesAndCheckVersion(OperationContext* opCtx) {
                     // On startup, if the version is in an upgrading or downrading state, print a
                     // warning.
                     if (version ==
-                        ServerGlobalParams::FeatureCompatibility::Version::kUpgradingTo40) {
+                        ServerGlobalParams::FeatureCompatibility::Version::kUpgradingTo42) {
                         log() << "** WARNING: A featureCompatibilityVersion upgrade did not "
                               << "complete. " << startupWarningsLog;
                         log() << "**          The current featureCompatibilityVersion is "
                               << FeatureCompatibilityVersionParser::toString(version) << "."
                               << startupWarningsLog;
                         log() << "**          To fix this, use the setFeatureCompatibilityVersion "
-                              << "command to resume upgrade to 4.0." << startupWarningsLog;
+                              << "command to resume upgrade to 4.2." << startupWarningsLog;
                     } else if (version == ServerGlobalParams::FeatureCompatibility::Version::
-                                              kDowngradingTo36) {
+                                              kDowngradingTo40) {
                         log() << "** WARNING: A featureCompatibilityVersion downgrade did not "
                               << "complete. " << startupWarningsLog;
                         log() << "**          The current featureCompatibilityVersion is "
                               << FeatureCompatibilityVersionParser::toString(version) << "."
                               << startupWarningsLog;
                         log() << "**          To fix this, use the setFeatureCompatibilityVersion "
-                              << "command to resume downgrade to 3.6." << startupWarningsLog;
+                              << "command to resume downgrade to 4.0." << startupWarningsLog;
                     }
                 }
             }
diff --git a/src/mongo/db/repl/initial_syncer.cpp b/src/mongo/db/repl/initial_syncer.cpp
index 2268129f0b3..bcf6ae2b6d4 100644
--- a/src/mongo/db/repl/initial_syncer.cpp
+++ b/src/mongo/db/repl/initial_syncer.cpp
@@ -728,8 +728,8 @@ void InitialSyncer::_fcvFetcherCallback(const StatusWith<Fetcher::QueryResponse>
     auto version = fCVParseSW.getValue();
 
     // Changing the featureCompatibilityVersion during initial sync is unsafe.
-    if (version > ServerGlobalParams::FeatureCompatibility::Version::kFullyDowngradedTo36 &&
-        version < ServerGlobalParams::FeatureCompatibility::Version::kFullyUpgradedTo40) {
+    if (version > ServerGlobalParams::FeatureCompatibility::Version::kFullyDowngradedTo40 &&
+        version < ServerGlobalParams::FeatureCompatibility::Version::kFullyUpgradedTo42) {
         onCompletionGuard->setResultAndCancelRemainingWork_inlock(
             lock,
             Status(ErrorCodes::IncompatibleServerVersion,
diff --git a/src/mongo/db/repl/initial_syncer_test.cpp b/src/mongo/db/repl/initial_syncer_test.cpp
index 98a18d6c75f..0f0f95e9fa1 100644
--- a/src/mongo/db/repl/initial_syncer_test.cpp
+++ b/src/mongo/db/repl/initial_syncer_test.cpp
@@ -200,10 +200,10 @@ public:
 
     /**
      * Schedules and processes a successful response to the network request sent by InitialSyncer's
-     * feature compatibility version fetcher. Always includes a valid fCV=3.6 document in the
+     * feature compatibility version fetcher. Always includes a valid fCV=4.0 document in the
      * response.
      */
-    void processSuccessfulFCVFetcherResponse36();
+    void processSuccessfulFCVFetcherResponse40();
 
     void finishProcessingNetworkResponse() {
         getNet()->runReadyNetworkOperations();
@@ -591,9 +591,9 @@ void assertFCVRequest(RemoteCommandRequest request) {
                       request.cmdObj.getObjectField("filter"));
 }
 
-void InitialSyncerTest::processSuccessfulFCVFetcherResponse36() {
+void InitialSyncerTest::processSuccessfulFCVFetcherResponse40() {
     auto docs = {BSON("_id" << FeatureCompatibilityVersionParser::kParameterName << "version"
-                            << FeatureCompatibilityVersionParser::kVersion36)};
+                            << FeatureCompatibilityVersionParser::kVersion40)};
     processSuccessfulFCVFetcherResponse(docs);
 }
 
@@ -1347,7 +1347,7 @@ TEST_F(InitialSyncerTest,
         processSuccessfulLastOplogEntryFetcherResponse({makeOplogEntryObj(1)});
 
         // Feature Compatibility Version.
-        processSuccessfulFCVFetcherResponse36();
+        processSuccessfulFCVFetcherResponse40();
     }
 
     initialSyncer->join();
@@ -1475,7 +1475,7 @@ TEST_F(InitialSyncerTest, InitialSyncerResendsFindCommandIfFCVFetcherReturnsRetr
     ASSERT_TRUE(initialSyncer->isActive());
 
     // FCV second attempt.
-    processSuccessfulFCVFetcherResponse36();
+    processSuccessfulFCVFetcherResponse40();
 }
 
 void InitialSyncerTest::runInitialSyncWithBadFCVResponse(std::vector<BSONObj> docs,
@@ -1512,7 +1512,7 @@ TEST_F(InitialSyncerTest,
 TEST_F(InitialSyncerTest,
        InitialSyncerReturnsTooManyMatchingDocumentsWhenFCVFetcherReturnsMultipleDocuments) {
     auto docs = {BSON("_id" << FeatureCompatibilityVersionParser::kParameterName << "version"
-                            << FeatureCompatibilityVersionParser::kVersion36),
+                            << FeatureCompatibilityVersionParser::kVersion40),
                  BSON("_id"
                       << "other")};
     runInitialSyncWithBadFCVResponse(docs, ErrorCodes::TooManyMatchingDocuments);
@@ -1521,24 +1521,24 @@ TEST_F(InitialSyncerTest,
 TEST_F(InitialSyncerTest,
        InitialSyncerReturnsIncompatibleServerVersionWhenFCVFetcherReturnsUpgradeTargetVersion) {
     auto docs = {BSON("_id" << FeatureCompatibilityVersionParser::kParameterName << "version"
-                            << FeatureCompatibilityVersionParser::kVersion36
+                            << FeatureCompatibilityVersionParser::kVersion40
                             << "targetVersion"
-                            << FeatureCompatibilityVersionParser::kVersion40)};
+                            << FeatureCompatibilityVersionParser::kVersion42)};
     runInitialSyncWithBadFCVResponse(docs, ErrorCodes::IncompatibleServerVersion);
 }
 
 TEST_F(InitialSyncerTest,
        InitialSyncerReturnsIncompatibleServerVersionWhenFCVFetcherReturnsDowngradeTargetVersion) {
     auto docs = {BSON("_id" << FeatureCompatibilityVersionParser::kParameterName << "version"
-                            << FeatureCompatibilityVersionParser::kVersion36
+                            << FeatureCompatibilityVersionParser::kVersion40
                             << "targetVersion"
-                            << FeatureCompatibilityVersionParser::kVersion36)};
+                            << FeatureCompatibilityVersionParser::kVersion40)};
     runInitialSyncWithBadFCVResponse(docs, ErrorCodes::IncompatibleServerVersion);
 }
 
 TEST_F(InitialSyncerTest, InitialSyncerReturnsBadValueWhenFCVFetcherReturnsNoVersion) {
     auto docs = {BSON("_id" << FeatureCompatibilityVersionParser::kParameterName << "targetVersion"
-                            << FeatureCompatibilityVersionParser::kVersion36)};
+                            << FeatureCompatibilityVersionParser::kVersion40)};
     runInitialSyncWithBadFCVResponse(docs, ErrorCodes::BadValue);
 }
 
@@ -1561,7 +1561,7 @@ TEST_F(InitialSyncerTest, InitialSyncerSucceedsWhenFCVFetcherReturnsOldVersion)
         processSuccessfulLastOplogEntryFetcherResponse({makeOplogEntryObj(1)});
 
         auto docs = {BSON("_id" << FeatureCompatibilityVersionParser::kParameterName << "version"
-                                << FeatureCompatibilityVersionParser::kVersion36)};
+                                << FeatureCompatibilityVersionParser::kVersion40)};
         processSuccessfulFCVFetcherResponse(docs);
         ASSERT_TRUE(net->hasReadyRequests());
     }
@@ -1608,7 +1608,7 @@ TEST_F(InitialSyncerTest, InitialSyncerPassesThroughOplogFetcherScheduleError) {
         net->runReadyNetworkOperations();
 
         // Feature Compatibility Version.
-        processSuccessfulFCVFetcherResponse36();
+        processSuccessfulFCVFetcherResponse40();
 
         // OplogFetcher will shut down DatabasesCloner on error after setting the completion status.
         // We call runReadyNetworkOperations() again to deliver the cancellation status to
@@ -1646,7 +1646,7 @@ TEST_F(InitialSyncerTest, InitialSyncerPassesThroughOplogFetcherCallbackError) {
         net->runReadyNetworkOperations();
 
         // Feature Compatibility Version.
-        processSuccessfulFCVFetcherResponse36();
+        processSuccessfulFCVFetcherResponse40();
 
         assertRemoteCommandNameEquals(
             "listDatabases", net->scheduleSuccessfulResponse(makeListDatabasesResponse({})));
@@ -1694,7 +1694,7 @@ TEST_F(InitialSyncerTest,
         net->runReadyNetworkOperations();
 
         // Feature Compatibility Version.
-        processSuccessfulFCVFetcherResponse36();
+        processSuccessfulFCVFetcherResponse40();
 
         assertRemoteCommandNameEquals(
             "listDatabases", net->scheduleSuccessfulResponse(makeListDatabasesResponse({})));
@@ -1743,7 +1743,7 @@ TEST_F(
         processSuccessfulLastOplogEntryFetcherResponse({makeOplogEntryObj(1)});
 
         // Feature Compatibility Version.
-        processSuccessfulFCVFetcherResponse36();
+        processSuccessfulFCVFetcherResponse40();
 
         assertRemoteCommandNameEquals(
             "listDatabases", net->scheduleSuccessfulResponse(makeListDatabasesResponse({})));
@@ -1796,7 +1796,7 @@ TEST_F(
         processSuccessfulLastOplogEntryFetcherResponse({makeOplogEntryObj(1)});
 
         // Feature Compatibility Version.
-        processSuccessfulFCVFetcherResponse36();
+        processSuccessfulFCVFetcherResponse40();
 
         assertRemoteCommandNameEquals(
             "listDatabases", net->scheduleSuccessfulResponse(makeListDatabasesResponse({})));
@@ -1857,7 +1857,7 @@ TEST_F(InitialSyncerTest,
         processSuccessfulLastOplogEntryFetcherResponse({makeOplogEntryObj(1)});
 
         // Feature Compatibility Version.
-        processSuccessfulFCVFetcherResponse36();
+        processSuccessfulFCVFetcherResponse40();
 
         // InitialSyncer shuts down OplogFetcher when it fails to schedule DatabasesCloner
         // so we should not expect any network requests in the queue.
@@ -1897,7 +1897,7 @@ TEST_F(InitialSyncerTest,
         processSuccessfulLastOplogEntryFetcherResponse({makeOplogEntryObj(1)});
 
         // Feature Compatibility Version.
-        processSuccessfulFCVFetcherResponse36();
+        processSuccessfulFCVFetcherResponse40();
 
         // DatabasesCloner's first remote command - listDatabases
         assertRemoteCommandNameEquals(
@@ -1934,7 +1934,7 @@ TEST_F(InitialSyncerTest, InitialSyncerIgnoresLocalDatabasesWhenCloningDatabases
         processSuccessfulLastOplogEntryFetcherResponse({makeOplogEntryObj(1)});
 
         // Feature Compatibility Version.
-        processSuccessfulFCVFetcherResponse36();
+        processSuccessfulFCVFetcherResponse40();
 
         // DatabasesCloner's first remote command - listDatabases
         assertRemoteCommandNameEquals(
@@ -1997,7 +1997,7 @@ TEST_F(InitialSyncerTest,
         processSuccessfulLastOplogEntryFetcherResponse({makeOplogEntryObj(1)});
 
         // Feature Compatibility Version.
-        processSuccessfulFCVFetcherResponse36();
+        processSuccessfulFCVFetcherResponse40();
 
         // DatabasesCloner's first remote command - listDatabases
         assertRemoteCommandNameEquals(
@@ -2066,7 +2066,7 @@ TEST_F(InitialSyncerTest, InitialSyncerCancelsBothOplogFetcherAndDatabasesCloner
         processSuccessfulLastOplogEntryFetcherResponse({makeOplogEntryObj(1)});
 
         // Feature Compatibility Version.
-        processSuccessfulFCVFetcherResponse36();
+        processSuccessfulFCVFetcherResponse40();
     }
 
     ASSERT_OK(initialSyncer->shutdown());
@@ -2115,7 +2115,7 @@ TEST_F(InitialSyncerTest,
         processSuccessfulLastOplogEntryFetcherResponse({makeOplogEntryObj(1)});
 
         // Feature Compatibility Version.
-        processSuccessfulFCVFetcherResponse36();
+        processSuccessfulFCVFetcherResponse40();
 
         // Quickest path to a successful DatabasesCloner completion is to respond to the
         // listDatabases with an empty list of database names.
@@ -2154,7 +2154,7 @@ TEST_F(InitialSyncerTest,
         processSuccessfulLastOplogEntryFetcherResponse({makeOplogEntryObj(1)});
 
         // Feature Compatibility Version.
-        processSuccessfulFCVFetcherResponse36();
+        processSuccessfulFCVFetcherResponse40();
 
         // Quickest path to a successful DatabasesCloner completion is to respond to the
         // listDatabases with an empty list of database names.
@@ -2209,7 +2209,7 @@ TEST_F(InitialSyncerTest,
         processSuccessfulLastOplogEntryFetcherResponse({makeOplogEntryObj(1)});
 
         // Feature Compatibility Version.
-        processSuccessfulFCVFetcherResponse36();
+        processSuccessfulFCVFetcherResponse40();
 
         // Quickest path to a successful DatabasesCloner completion is to respond to the
         // listDatabases with an empty list of database names.
@@ -2259,7 +2259,7 @@ TEST_F(InitialSyncerTest,
         processSuccessfulLastOplogEntryFetcherResponse({makeOplogEntryObj(1)});
 
         // Feature Compatibility Version.
-        processSuccessfulFCVFetcherResponse36();
+        processSuccessfulFCVFetcherResponse40();
 
         // Quickest path to a successful DatabasesCloner completion is to respond to the
         // listDatabases with an empty list of database names.
@@ -2320,7 +2320,7 @@ TEST_F(
         processSuccessfulLastOplogEntryFetcherResponse({oplogEntry});
 
         // Feature Compatibility Version.
-        processSuccessfulFCVFetcherResponse36();
+        processSuccessfulFCVFetcherResponse40();
 
         // Quickest path to a successful DatabasesCloner completion is to respond to the
         // listDatabases with an empty list of database names.
@@ -2371,7 +2371,7 @@ TEST_F(InitialSyncerTest,
         processSuccessfulLastOplogEntryFetcherResponse({makeOplogEntryObj(2)});
 
         // Feature Compatibility Version.
-        processSuccessfulFCVFetcherResponse36();
+        processSuccessfulFCVFetcherResponse40();
 
         // Quickest path to a successful DatabasesCloner completion is to respond to the
         // listDatabases with an empty list of database names.
@@ -2437,7 +2437,7 @@ TEST_F(
         processSuccessfulLastOplogEntryFetcherResponse({oplogEntry});
 
         // Feature Compatibility Version.
-        processSuccessfulFCVFetcherResponse36();
+        processSuccessfulFCVFetcherResponse40();
 
         // Quickest path to a successful DatabasesCloner completion is to respond to the
         // listDatabases with an empty list of database names.
@@ -2506,7 +2506,7 @@ TEST_F(
         processSuccessfulLastOplogEntryFetcherResponse({oplogEntry});
 
         // Feature Compatibility Version.
-        processSuccessfulFCVFetcherResponse36();
+        processSuccessfulFCVFetcherResponse40();
 
         // Quickest path to a successful DatabasesCloner completion is to respond to the
         // listDatabases with an empty list of database names.
@@ -2575,7 +2575,7 @@ TEST_F(
         processSuccessfulLastOplogEntryFetcherResponse({oplogEntry});
 
         // Feature Compatibility Version.
-        processSuccessfulFCVFetcherResponse36();
+        processSuccessfulFCVFetcherResponse40();
 
         // Quickest path to a successful DatabasesCloner completion is to respond to the
         // listDatabases with an empty list of database names.
@@ -2626,7 +2626,7 @@ TEST_F(
         processSuccessfulLastOplogEntryFetcherResponse({oplogEntry});
 
         // Feature Compatibility Version.
-        processSuccessfulFCVFetcherResponse36();
+        processSuccessfulFCVFetcherResponse40();
 
         // Quickest path to a successful DatabasesCloner completion is to respond to the
         // listDatabases with an empty list of database names.
@@ -2682,7 +2682,7 @@ TEST_F(InitialSyncerTest, InitialSyncerCancelsLastRollbackCheckerOnShutdown) {
         processSuccessfulLastOplogEntryFetcherResponse({oplogEntry});
 
         // Feature Compatibility Version.
-        processSuccessfulFCVFetcherResponse36();
+        processSuccessfulFCVFetcherResponse40();
 
         // Quickest path to a successful DatabasesCloner completion is to respond to the
         // listDatabases with an empty list of database names.
@@ -2739,7 +2739,7 @@ TEST_F(InitialSyncerTest, InitialSyncerCancelsLastRollbackCheckerOnOplogFetcherC
         processSuccessfulLastOplogEntryFetcherResponse({oplogEntry});
 
         // Feature Compatibility Version.
-        processSuccessfulFCVFetcherResponse36();
+        processSuccessfulFCVFetcherResponse40();
 
         // Quickest path to a successful DatabasesCloner completion is to respond to the
         // listDatabases with an empty list of database names.
@@ -2801,7 +2801,7 @@ TEST_F(InitialSyncerTest,
         processSuccessfulLastOplogEntryFetcherResponse({oplogEntry});
 
         // Feature Compatibility Version.
-        processSuccessfulFCVFetcherResponse36();
+        processSuccessfulFCVFetcherResponse40();
 
         // Quickest path to a successful DatabasesCloner completion is to respond to the
         // listDatabases with an empty list of database names.
@@ -2854,7 +2854,7 @@ TEST_F(InitialSyncerTest, LastOpTimeShouldBeSetEvenIfNoOperationsAreAppliedAfter
         processSuccessfulLastOplogEntryFetcherResponse({oplogEntry.toBSON()});
 
         // Feature Compatibility Version.
-        processSuccessfulFCVFetcherResponse36();
+        processSuccessfulFCVFetcherResponse40();
 
         // Instead of fast forwarding to DatabasesCloner completion by returning an empty list of
         // database names, we'll simulate copying a single database with a single collection on the
@@ -2945,7 +2945,7 @@ TEST_F(InitialSyncerTest, InitialSyncerPassesThroughGetNextApplierBatchScheduleE
         processSuccessfulLastOplogEntryFetcherResponse({makeOplogEntryObj(1)});
 
         // Feature Compatibility Version.
-        processSuccessfulFCVFetcherResponse36();
+        processSuccessfulFCVFetcherResponse40();
 
         // Quickest path to a successful DatabasesCloner completion is to respond to the
         // listDatabases with an empty list of database names.
@@ -3002,7 +3002,7 @@ TEST_F(InitialSyncerTest, InitialSyncerPassesThroughSecondGetNextApplierBatchSch
         processSuccessfulLastOplogEntryFetcherResponse({makeOplogEntryObj(1)});
 
         // Feature Compatibility Version.
-        processSuccessfulFCVFetcherResponse36();
+        processSuccessfulFCVFetcherResponse40();
 
         // Quickest path to a successful DatabasesCloner completion is to respond to the
         // listDatabases with an empty list of database names.
@@ -3059,7 +3059,7 @@ TEST_F(InitialSyncerTest, InitialSyncerCancelsGetNextApplierBatchOnShutdown) {
         processSuccessfulLastOplogEntryFetcherResponse({makeOplogEntryObj(1)});
 
         // Feature Compatibility Version.
-        processSuccessfulFCVFetcherResponse36();
+        processSuccessfulFCVFetcherResponse40();
 
         // Quickest path to a successful DatabasesCloner completion is to respond to the
         // listDatabases with an empty list of database names.
@@ -3118,7 +3118,7 @@ TEST_F(InitialSyncerTest, InitialSyncerPassesThroughGetNextApplierBatchInLockErr
         processSuccessfulLastOplogEntryFetcherResponse({makeOplogEntryObj(1)});
 
         // Feature Compatibility Version.
-        processSuccessfulFCVFetcherResponse36();
+        processSuccessfulFCVFetcherResponse40();
 
         // Quickest path to a successful DatabasesCloner completion is to respond to the
         // listDatabases with an empty list of database names.
@@ -3185,7 +3185,7 @@ TEST_F(
         processSuccessfulLastOplogEntryFetcherResponse({makeOplogEntryObj(1)});
 
         // Feature Compatibility Version.
-        processSuccessfulFCVFetcherResponse36();
+        processSuccessfulFCVFetcherResponse40();
 
         // Quickest path to a successful DatabasesCloner completion is to respond to the
         // listDatabases with an empty list of database names.
@@ -3243,7 +3243,7 @@ TEST_F(InitialSyncerTest, InitialSyncerPassesThroughMultiApplierScheduleError) {
         processSuccessfulLastOplogEntryFetcherResponse({makeOplogEntryObj(1)});
 
         // Feature Compatibility Version.
-        processSuccessfulFCVFetcherResponse36();
+        processSuccessfulFCVFetcherResponse40();
 
         // Quickest path to a successful DatabasesCloner completion is to respond to the
         // listDatabases with an empty list of database names.
@@ -3317,7 +3317,7 @@ TEST_F(InitialSyncerTest, InitialSyncerPassesThroughMultiApplierCallbackError) {
         processSuccessfulLastOplogEntryFetcherResponse({makeOplogEntryObj(1)});
 
         // Feature Compatibility Version.
-        processSuccessfulFCVFetcherResponse36();
+        processSuccessfulFCVFetcherResponse40();
 
         // Quickest path to a successful DatabasesCloner completion is to respond to the
         // listDatabases with an empty list of database names.
@@ -3366,7 +3366,7 @@ TEST_F(InitialSyncerTest, InitialSyncerCancelsGetNextApplierBatchCallbackOnOplog
         processSuccessfulLastOplogEntryFetcherResponse({makeOplogEntryObj(1)});
 
         // Feature Compatibility Version.
-        processSuccessfulFCVFetcherResponse36();
+        processSuccessfulFCVFetcherResponse40();
 
         // Quickest path to a successful DatabasesCloner completion is to respond to the
         // listDatabases with an empty list of database names.
@@ -3421,7 +3421,7 @@ OplogEntry InitialSyncerTest::doInitialSyncWithOneBatch(bool shouldSetFCV) {
         processSuccessfulLastOplogEntryFetcherResponse({makeOplogEntryObj(1)});
 
         // Feature Compatibility Version.
-        processSuccessfulFCVFetcherResponse36();
+        processSuccessfulFCVFetcherResponse40();
 
         // Quickest path to a successful DatabasesCloner completion is to respond to the
         // listDatabases with an empty list of database names.
@@ -3515,7 +3515,7 @@ TEST_F(InitialSyncerTest,
         processSuccessfulLastOplogEntryFetcherResponse({makeOplogEntryObj(1)});
 
         // Feature Compatibility Version.
-        processSuccessfulFCVFetcherResponse36();
+        processSuccessfulFCVFetcherResponse40();
 
         // Instead of fast forwarding to DatabasesCloner completion by returning an empty list of
         // database names, we'll simulate copying a single database with a single collection on the
@@ -3633,7 +3633,7 @@ TEST_F(
         processSuccessfulLastOplogEntryFetcherResponse({makeOplogEntryObj(1)});
 
         // Feature Compatibility Version.
-        processSuccessfulFCVFetcherResponse36();
+        processSuccessfulFCVFetcherResponse40();
 
         // Quickest path to a successful DatabasesCloner completion is to respond to the
         // listDatabases with an empty list of database names.
@@ -3725,7 +3725,7 @@ TEST_F(InitialSyncerTest, OplogOutOfOrderOnOplogFetchFinish) {
         processSuccessfulLastOplogEntryFetcherResponse({makeOplogEntryObj(1)});
 
         // Feature Compatibility Version.
-        processSuccessfulFCVFetcherResponse36();
+        processSuccessfulFCVFetcherResponse40();
 
         // Ignore listDatabases request.
         auto noi = net->getNextReadyRequest();
@@ -3779,7 +3779,7 @@ TEST_F(InitialSyncerTest, GetInitialSyncProgressReturnsCorrectProgress) {
         processSuccessfulLastOplogEntryFetcherResponse({makeOplogEntryObj(1)});
 
         // Feature Compatibility Version.
-        processSuccessfulFCVFetcherResponse36();
+        processSuccessfulFCVFetcherResponse40();
     }
 
     log() << "Done playing first failed response";
@@ -3828,7 +3828,7 @@ TEST_F(InitialSyncerTest, GetInitialSyncProgressReturnsCorrectProgress) {
         processSuccessfulLastOplogEntryFetcherResponse({makeOplogEntryObj(1)});
 
         // Feature Compatibility Version.
-        processSuccessfulFCVFetcherResponse36();
+        processSuccessfulFCVFetcherResponse40();
     }
 
     log() << "Done playing first successful response";
@@ -4041,7 +4041,7 @@ TEST_F(InitialSyncerTest, GetInitialSyncProgressOmitsClonerStatsIfClonerStatsExc
         processSuccessfulLastOplogEntryFetcherResponse({makeOplogEntryObj(1)});
 
         // Feature Compatibility Version.
-        processSuccessfulFCVFetcherResponse36();
+        processSuccessfulFCVFetcherResponse40();
 
         // listDatabases
         NamespaceString nss("a.a");
diff --git a/src/mongo/db/repl/replication_coordinator_impl.cpp b/src/mongo/db/repl/replication_coordinator_impl.cpp
index 828ac2622ad..35875f1bb33 100644
--- a/src/mongo/db/repl/replication_coordinator_impl.cpp
+++ b/src/mongo/db/repl/replication_coordinator_impl.cpp
@@ -2534,7 +2534,7 @@ ReplicationCoordinatorImpl::_updateMemberStateFromTopologyCoordinator_inlock(
     // receive the replicated version. This is to avoid bugs like SERVER-32639.
     if (newState.arbiter()) {
         serverGlobalParams.featureCompatibility.setVersion(
-            ServerGlobalParams::FeatureCompatibility::Version::kFullyUpgradedTo40);
+            ServerGlobalParams::FeatureCompatibility::Version::kFullyUpgradedTo42);
     }
 
     _memberState = newState;
diff --git a/src/mongo/db/repl/replication_info.cpp b/src/mongo/db/repl/replication_info.cpp
index 3782148a7d6..3c594a75492 100644
--- a/src/mongo/db/repl/replication_info.cpp
+++ b/src/mongo/db/repl/replication_info.cpp
@@ -57,7 +57,6 @@
 #include "mongo/executor/network_interface.h"
 #include "mongo/rpc/metadata/client_metadata.h"
 #include "mongo/rpc/metadata/client_metadata_ismaster.h"
-#include "mongo/util/fail_point_service.h"
 #include "mongo/util/map_util.h"
 
 namespace mongo {
@@ -69,12 +68,6 @@ using std::stringstream;
 
 namespace repl {
 
-namespace {
-
-MONGO_FAIL_POINT_DEFINE(impersonateFullyUpgradedFutureVersion);
-
-}  // namespace
-
 void appendReplicationInfo(OperationContext* opCtx, BSONObjBuilder& result, int level) {
     ReplicationCoordinator* replCoord = ReplicationCoordinator::get(opCtx);
     if (replCoord->getSettings().usingReplSets()) {
@@ -355,10 +348,7 @@ public:
         result.append("logicalSessionTimeoutMinutes", localLogicalSessionTimeoutMinutes);
         result.appendNumber("connectionId", opCtx->getClient()->getConnectionId());
 
-        if (MONGO_FAIL_POINT(impersonateFullyUpgradedFutureVersion)) {
-            result.append("minWireVersion", WireVersion::FUTURE_WIRE_VERSION_FOR_TESTING);
-            result.append("maxWireVersion", WireVersion::FUTURE_WIRE_VERSION_FOR_TESTING);
-        } else if (internalClientElement) {
+        if (internalClientElement) {
             result.append("minWireVersion",
                           WireSpec::instance().incomingInternalClient.minWireVersion);
             result.append("maxWireVersion",
diff --git a/src/mongo/db/repl/sync_tail_test_fixture.cpp b/src/mongo/db/repl/sync_tail_test_fixture.cpp
index b3b7980a470..dc1ed3dec95 100644
--- a/src/mongo/db/repl/sync_tail_test_fixture.cpp
+++ b/src/mongo/db/repl/sync_tail_test_fixture.cpp
@@ -121,7 +121,7 @@ void SyncTailTest::setUp() {
     // test fixture does not create a featureCompatibilityVersion document from which to initialize
     // the server parameter.
     serverGlobalParams.featureCompatibility.setVersion(
-        ServerGlobalParams::FeatureCompatibility::Version::kFullyUpgradedTo40);
+        ServerGlobalParams::FeatureCompatibility::Version::kFullyUpgradedTo42);
 }
 
 void SyncTailTest::tearDown() {
diff --git a/src/mongo/db/s/config/configsvr_shard_collection_command.cpp b/src/mongo/db/s/config/configsvr_shard_collection_command.cpp
index bdaa4e5510f..125dc67569e 100644
--- a/src/mongo/db/s/config/configsvr_shard_collection_command.cpp
+++ b/src/mongo/db/s/config/configsvr_shard_collection_command.cpp
@@ -666,7 +666,7 @@ boost::optional<UUID> getUUIDFromPrimaryShard(const NamespaceString& nss,
             str::stream() << "expected primary shard to return 'info' field as part of "
                              "listCollections for "
                           << nss.ns()
-                          << " because the cluster is in featureCompatibilityVersion=3.6, but got "
+                          << ", but got "
                           << res,
             !collectionInfo.isEmpty());
 
diff --git a/src/mongo/db/s/config/sharding_catalog_manager_add_shard_test.cpp b/src/mongo/db/s/config/sharding_catalog_manager_add_shard_test.cpp
index f0e5aa84f5e..74587e60d3e 100644
--- a/src/mongo/db/s/config/sharding_catalog_manager_add_shard_test.cpp
+++ b/src/mongo/db/s/config/sharding_catalog_manager_add_shard_test.cpp
@@ -144,7 +144,7 @@ protected:
             ASSERT_EQ(request.dbname, "admin");
             ASSERT_BSONOBJ_EQ(request.cmdObj,
                               BSON("setFeatureCompatibilityVersion"
-                                   << "4.0"
+                                   << "4.2"
                                    << "writeConcern"
                                    << writeConcern));
 
diff --git a/src/mongo/db/s/config/sharding_catalog_manager_shard_operations.cpp b/src/mongo/db/s/config/sharding_catalog_manager_shard_operations.cpp
index 85831492b73..7d11f8e316b 100644
--- a/src/mongo/db/s/config/sharding_catalog_manager_shard_operations.cpp
+++ b/src/mongo/db/s/config/sharding_catalog_manager_shard_operations.cpp
@@ -343,14 +343,14 @@ StatusWith<ShardType> ShardingCatalogManager::_validateHostAsShard(
                                                 << " as a shard");
     }
     if (serverGlobalParams.featureCompatibility.getVersion() >
-        ServerGlobalParams::FeatureCompatibility::Version::kFullyDowngradedTo36) {
-        // If the cluster's FCV is 4.0, or upgrading to / downgrading from, the node being added
-        // must be a v4.0 binary.
+        ServerGlobalParams::FeatureCompatibility::Version::kFullyDowngradedTo40) {
+        // If the cluster's FCV is 4.2, or upgrading to / downgrading from, the node being added
+        // must be a v4.2 binary.
         invariant(maxWireVersion == WireVersion::LATEST_WIRE_VERSION);
     } else {
-        // If the cluster's FCV is 3.6, the node being added must be a v3.6 or v4.0 binary.
+        // If the cluster's FCV is 4.0, the node being added must be a v4.0 or v4.2 binary.
         invariant(serverGlobalParams.featureCompatibility.getVersion() ==
-                  ServerGlobalParams::FeatureCompatibility::Version::kFullyDowngradedTo36);
+                  ServerGlobalParams::FeatureCompatibility::Version::kFullyDowngradedTo40);
         invariant(maxWireVersion >= WireVersion::LATEST_WIRE_VERSION - 1);
     }
 
@@ -702,16 +702,16 @@ StatusWith<std::string> ShardingCatalogManager::addShard(
 
         BSONObj setFCVCmd;
         switch (serverGlobalParams.featureCompatibility.getVersion()) {
-            case ServerGlobalParams::FeatureCompatibility::Version::kFullyUpgradedTo40:
-            case ServerGlobalParams::FeatureCompatibility::Version::kUpgradingTo40:
+            case ServerGlobalParams::FeatureCompatibility::Version::kFullyUpgradedTo42:
+            case ServerGlobalParams::FeatureCompatibility::Version::kUpgradingTo42:
                 setFCVCmd = BSON(FeatureCompatibilityVersionCommandParser::kCommandName
-                                 << FeatureCompatibilityVersionParser::kVersion40
+                                 << FeatureCompatibilityVersionParser::kVersion42
                                  << WriteConcernOptions::kWriteConcernField
                                  << opCtx->getWriteConcern().toBSON());
                 break;
             default:
                 setFCVCmd = BSON(FeatureCompatibilityVersionCommandParser::kCommandName
-                                 << FeatureCompatibilityVersionParser::kVersion36
+                                 << FeatureCompatibilityVersionParser::kVersion40
                                  << WriteConcernOptions::kWriteConcernField
                                  << opCtx->getWriteConcern().toBSON());
                 break;
diff --git a/src/mongo/db/server_options.h b/src/mongo/db/server_options.h
index f4abfe9a884..25f7a7ccc42 100644
--- a/src/mongo/db/server_options.h
+++ b/src/mongo/db/server_options.h
@@ -155,40 +155,40 @@ struct ServerGlobalParams {
          *
          * The legal enum (and featureCompatibilityVersion document) states are:
          *
-         * kFullyDowngradedTo36
-         * (3.6, Unset): Only 3.6 features are available, and new and existing storage
-         *               engine entries use the 3.6 format
+         * kFullyDowngradedTo40
+         * (4.0, Unset): Only 4.0 features are available, and new and existing storage
+         *               engine entries use the 4.0 format
          *
-         * kUpgradingTo40
-         * (3.6, 4.0): Only 3.6 features are available, but new storage engine entries
-         *             use the 4.0 format, and existing entries may have either the
-         *             3.6 or 4.0 format
+         * kUpgradingTo42
+         * (4.0, 4.2): Only 4.0 features are available, but new storage engine entries
+         *             use the 4.2 format, and existing entries may have either the
+         *             4.0 or 4.2 format
          *
-         * kFullyUpgradedTo40
-         * (4.0, Unset): 4.0 features are available, and new and existing storage
-         *               engine entries use the 4.0 format
+         * kFullyUpgradedTo42
+         * (4.2, Unset): 4.2 features are available, and new and existing storage
+         *               engine entries use the 4.2 format
          *
-         * kDowngradingTo36
-         * (3.6, 3.6): Only 3.6 features are available and new storage engine
-         *             entries use the 3.6 format, but existing entries may have
-         *             either the 3.6 or 4.0 format
+         * kDowngradingTo40
+         * (4.0, 4.0): Only 4.0 features are available and new storage engine
+         *             entries use the 4.0 format, but existing entries may have
+         *             either the 4.0 or 4.2 format
          *
-         * kUnsetDefault36Behavior
+         * kUnsetDefault40Behavior
          * (Unset, Unset): This is the case on startup before the fCV document is
          *                 loaded into memory. isVersionInitialized() will return
          *                 false, and getVersion() will return the default
-         *                 (kFullyDowngradedTo36).
+         *                 (kFullyDowngradedTo40).
          *
          */
         enum class Version {
             // The order of these enums matter, higher upgrades having higher values, so that
             // features can be active or inactive if the version is higher than some minimum or
             // lower than some maximum, respectively.
-            kUnsetDefault36Behavior = 0,
-            kFullyDowngradedTo36 = 1,
-            kDowngradingTo36 = 2,
-            kUpgradingTo40 = 3,
-            kFullyUpgradedTo40 = 4,
+            kUnsetDefault40Behavior = 0,
+            kFullyDowngradedTo40 = 1,
+            kDowngradingTo40 = 2,
+            kUpgradingTo42 = 3,
+            kFullyUpgradedTo42 = 4,
         };
 
         /**
@@ -196,7 +196,7 @@ struct ServerGlobalParams {
          * exposes the actual state of the featureCompatibilityVersion if it is uninitialized.
          */
         const bool isVersionInitialized() const {
-            return _version.load() != Version::kUnsetDefault36Behavior;
+            return _version.load() != Version::kUnsetDefault40Behavior;
         }
 
         /**
@@ -216,11 +216,11 @@ struct ServerGlobalParams {
          */
         const Version getVersionUnsafe() const {
             Version v = _version.load();
-            return (v == Version::kUnsetDefault36Behavior) ? Version::kFullyDowngradedTo36 : v;
+            return (v == Version::kUnsetDefault40Behavior) ? Version::kFullyDowngradedTo40 : v;
         }
 
         void reset() {
-            _version.store(Version::kUnsetDefault36Behavior);
+            _version.store(Version::kUnsetDefault40Behavior);
         }
 
         void setVersion(Version version) {
@@ -228,12 +228,12 @@ struct ServerGlobalParams {
         }
 
         bool isVersionUpgradingOrUpgraded() {
-            return (getVersion() == Version::kUpgradingTo40 ||
-                    getVersion() == Version::kFullyUpgradedTo40);
+            return (getVersion() == Version::kUpgradingTo42 ||
+                    getVersion() == Version::kFullyUpgradedTo42);
         }
 
     private:
-        AtomicWord<Version> _version{Version::kUnsetDefault36Behavior};
+        AtomicWord<Version> _version{Version::kUnsetDefault40Behavior};
 
     } featureCompatibility;
 
diff --git a/src/mongo/db/storage/wiredtiger/wiredtiger_kv_engine.cpp b/src/mongo/db/storage/wiredtiger/wiredtiger_kv_engine.cpp
index f5984adc33f..4e06354af8b 100644
--- a/src/mongo/db/storage/wiredtiger/wiredtiger_kv_engine.cpp
+++ b/src/mongo/db/storage/wiredtiger/wiredtiger_kv_engine.cpp
@@ -115,8 +115,8 @@ bool WiredTigerFileVersion::shouldDowngrade(bool readOnly,
     }
 
     if (serverGlobalParams.featureCompatibility.getVersion() !=
-        ServerGlobalParams::FeatureCompatibility::Version::kFullyDowngradedTo36) {
-        // Only consider downgrading when FCV is set to 3.6
+        ServerGlobalParams::FeatureCompatibility::Version::kFullyDowngradedTo40) {
+        // Only consider downgrading when FCV is set to 4.0
         return false;
     }
 
diff --git a/src/mongo/db/views/view_catalog.cpp b/src/mongo/db/views/view_catalog.cpp
index 27eb95d875d..107249c3d3d 100644
--- a/src/mongo/db/views/view_catalog.cpp
+++ b/src/mongo/db/views/view_catalog.cpp
@@ -254,11 +254,11 @@ StatusWith<stdx::unordered_set<NamespaceString>> ViewCatalog::_validatePipeline_
     // Save this to a variable to avoid reading the atomic variable multiple times.
     auto currentFCV = serverGlobalParams.featureCompatibility.getVersion();
 
-    // If the feature compatibility version is not 4.0, and we are validating features as master,
-    // ban the use of new agg features introduced in 4.0 to prevent them from being persisted in the
+    // If the feature compatibility version is not 4.2, and we are validating features as master,
+    // ban the use of new agg features introduced in 4.2 to prevent them from being persisted in the
     // catalog.
     if (serverGlobalParams.validateFeaturesAsMaster.load() &&
-        currentFCV != ServerGlobalParams::FeatureCompatibility::Version::kFullyUpgradedTo40) {
+        currentFCV != ServerGlobalParams::FeatureCompatibility::Version::kFullyUpgradedTo42) {
         expCtx->maxFeatureCompatibilityVersion = currentFCV;
     }
     auto pipelineStatus = Pipeline::parse(viewDef.pipeline(), std::move(expCtx));
diff --git a/src/mongo/db/wire_version.h b/src/mongo/db/wire_version.h
index 13ec8aa58b8..d373c648578 100644
--- a/src/mongo/db/wire_version.h
+++ b/src/mongo/db/wire_version.h
@@ -70,15 +70,15 @@ enum WireVersion {
     // Supports the new OP_MSG wireprotocol (3.6+).
     SUPPORTS_OP_MSG = 6,
 
-    // Supports replica set transactions (3.8+).
+    // Supports replica set transactions (4.0+).
     REPLICA_SET_TRANSACTIONS = 7,
 
+    // Supports sharded transactions (4.2+).
+    SHARDED_TRANSACTIONS = 8,
+
     // Set this to the highest value in this enum - it will be the default maxWireVersion for
     // the WireSpec values.
-    LATEST_WIRE_VERSION = REPLICA_SET_TRANSACTIONS,
-
-    // This is used in testing to masquerade as a future binary version node.
-    FUTURE_WIRE_VERSION_FOR_TESTING = 1 << 20,
+    LATEST_WIRE_VERSION = SHARDED_TRANSACTIONS,
 };
 
 /**
diff --git a/src/mongo/dbtests/dbtests.cpp b/src/mongo/dbtests/dbtests.cpp
index 2f89aa3354e..07a4b4fe915 100644
--- a/src/mongo/dbtests/dbtests.cpp
+++ b/src/mongo/dbtests/dbtests.cpp
@@ -165,7 +165,7 @@ int dbtestsMain(int argc, char** argv, char** envp) {
 
     mongo::runGlobalInitializersOrDie(argc, argv, envp);
     serverGlobalParams.featureCompatibility.setVersion(
-        ServerGlobalParams::FeatureCompatibility::Version::kFullyUpgradedTo40);
+        ServerGlobalParams::FeatureCompatibility::Version::kFullyUpgradedTo42);
     repl::ReplSettings replSettings;
     replSettings.setOplogSizeBytes(10 * 1024 * 1024);
     ServiceContext* service = getGlobalServiceContext();
diff --git a/src/mongo/rpc/protocol.cpp b/src/mongo/rpc/protocol.cpp
index ab5cbf8d47b..00fa6159ad4 100644
--- a/src/mongo/rpc/protocol.cpp
+++ b/src/mongo/rpc/protocol.cpp
@@ -181,7 +181,7 @@ ProtocolSet computeProtocolSet(const WireVersionInfo version) {
             result |= supports::kOpMsgOnly;
         }
         if (version.maxWireVersion >= WireVersion::FIND_COMMAND &&
-            version.maxWireVersion <= WireVersion::REPLICA_SET_TRANSACTIONS) {
+            version.maxWireVersion <= WireVersion::SHARDED_TRANSACTIONS) {
             // Future versions may remove support for OP_COMMAND.
             result |= supports::kOpCommandOnly;
         }
diff --git a/src/mongo/rpc/protocol_test.cpp b/src/mongo/rpc/protocol_test.cpp
index ab92e3eeae1..daa9e27a1b7 100644
--- a/src/mongo/rpc/protocol_test.cpp
+++ b/src/mongo/rpc/protocol_test.cpp
@@ -283,20 +283,19 @@ TEST(Protocol, validateWireVersion) {
 
 // A mongos is unable to communicate with a fully upgraded cluster with a higher wire version.
 TEST(Protocol, validateWireVersionFailsForUpgradedServerNode) {
-    // Server is fully upgraded higher than the latest wire version.
-    auto msg =
-        BSON("minWireVersion" << static_cast<int>(WireVersion::FUTURE_WIRE_VERSION_FOR_TESTING)
-                              << "maxWireVersion"
-                              << static_cast<int>(WireVersion::FUTURE_WIRE_VERSION_FOR_TESTING));
+    // Server is fully upgraded to the latest wire version.
+    auto msg = BSON("minWireVersion" << static_cast<int>(WireVersion::LATEST_WIRE_VERSION)
+                                     << "maxWireVersion"
+                                     << static_cast<int>(WireVersion::LATEST_WIRE_VERSION));
     auto swReply = parseProtocolSetFromIsMasterReply(msg);
     ASSERT_OK(swReply.getStatus());
 
-    // The client (this mongos server) only has latest wire version.
-    ASSERT_EQUALS(
-        mongo::ErrorCodes::IncompatibleWithUpgradedServer,
-        validateWireVersion({WireVersion::LATEST_WIRE_VERSION, WireVersion::LATEST_WIRE_VERSION},
-                            swReply.getValue().version)
-            .code());
+    // The client (this mongos server) only has the previous wire version.
+    ASSERT_EQUALS(mongo::ErrorCodes::IncompatibleWithUpgradedServer,
+                  validateWireVersion(
+                      {WireVersion::LATEST_WIRE_VERSION - 1, WireVersion::LATEST_WIRE_VERSION - 1},
+                      swReply.getValue().version)
+                      .code());
 }
 
 }  // namespace
diff --git a/src/mongo/s/commands/cluster_set_feature_compatibility_version_cmd.cpp b/src/mongo/s/commands/cluster_set_feature_compatibility_version_cmd.cpp
index 21278ac91a1..1d3fbfeaa68 100644
--- a/src/mongo/s/commands/cluster_set_feature_compatibility_version_cmd.cpp
+++ b/src/mongo/s/commands/cluster_set_feature_compatibility_version_cmd.cpp
@@ -71,11 +71,11 @@ public:
     std::string help() const override {
         return str::stream()
             << "Set the API version for the cluster. If set to \""
-            << FeatureCompatibilityVersionParser::kVersion36
-            << "\", then 4.0 features are disabled. If \""
             << FeatureCompatibilityVersionParser::kVersion40
-            << "\", then 4.0 features are enabled, and all nodes in the cluster must be version "
-            << "4.0. See " << feature_compatibility_version_documentation::kCompatibilityLink
+            << "\", then 4.2 features are disabled. If \""
+            << FeatureCompatibilityVersionParser::kVersion42
+            << "\", then 4.2 features are enabled, and all nodes in the cluster must be version "
+            << "4.2. See " << feature_compatibility_version_documentation::kCompatibilityLink
             << ".";
     }
 
diff --git a/src/mongo/s/server.cpp b/src/mongo/s/server.cpp
index 9e7358b2ca6..d5d38e1cc34 100644
--- a/src/mongo/s/server.cpp
+++ b/src/mongo/s/server.cpp
@@ -536,10 +536,10 @@ MONGO_INITIALIZER_GENERAL(ForkServer, ("EndStartupOptionHandling"), ("default"))
 // to the latest version because there is no feature gating that currently occurs at the mongos
 // level. The shards are responsible for rejecting usages of new features if their
 // featureCompatibilityVersion is lower.
-MONGO_INITIALIZER_WITH_PREREQUISITES(SetFeatureCompatibilityVersion40, ("EndStartupOptionStorage"))
+MONGO_INITIALIZER_WITH_PREREQUISITES(SetFeatureCompatibilityVersion42, ("EndStartupOptionStorage"))
 (InitializerContext* context) {
     serverGlobalParams.featureCompatibility.setVersion(
-        ServerGlobalParams::FeatureCompatibility::Version::kFullyUpgradedTo40);
+        ServerGlobalParams::FeatureCompatibility::Version::kFullyUpgradedTo42);
     return Status::OK();
 }
 
diff --git a/src/mongo/s/sharding_mongod_test_fixture.cpp b/src/mongo/s/sharding_mongod_test_fixture.cpp
index 6fa3565cab9..a91670bf753 100644
--- a/src/mongo/s/sharding_mongod_test_fixture.cpp
+++ b/src/mongo/s/sharding_mongod_test_fixture.cpp
@@ -146,7 +146,7 @@ void ShardingMongodTestFixture::setUp() {
     // Set the highest FCV because otherwise it defaults to the lower FCV. This way we default to
     // testing this release's code, not backwards compatibility code.
     serverGlobalParams.featureCompatibility.setVersion(
-        ServerGlobalParams::FeatureCompatibility::Version::kFullyUpgradedTo40);
+        ServerGlobalParams::FeatureCompatibility::Version::kFullyUpgradedTo42);
 }
 
 std::unique_ptr<ReplicationCoordinatorMock> ShardingMongodTestFixture::makeReplicationCoordinator(
diff --git a/src/mongo/shell/dbshell.cpp b/src/mongo/shell/dbshell.cpp
index 94b68ee43e3..bb0a82ffa02 100644
--- a/src/mongo/shell/dbshell.cpp
+++ b/src/mongo/shell/dbshell.cpp
@@ -97,10 +97,10 @@ const auto kDefaultMongoURL = "mongodb://127.0.0.1:27017"_sd;
 // to the latest version because there is no feature gating that currently occurs at the mongo shell
 // level. The server is responsible for rejecting usages of new features if its
 // featureCompatibilityVersion is lower.
-MONGO_INITIALIZER_WITH_PREREQUISITES(SetFeatureCompatibilityVersion40, ("EndStartupOptionSetup"))
+MONGO_INITIALIZER_WITH_PREREQUISITES(SetFeatureCompatibilityVersion42, ("EndStartupOptionSetup"))
 (InitializerContext* context) {
     mongo::serverGlobalParams.featureCompatibility.setVersion(
-        ServerGlobalParams::FeatureCompatibility::Version::kFullyUpgradedTo40);
+        ServerGlobalParams::FeatureCompatibility::Version::kFullyUpgradedTo42);
     return Status::OK();
 }
 const auto kAuthParam = "authSource"s;
diff --git a/src/mongo/shell/shardingtest.js b/src/mongo/shell/shardingtest.js
index 29f710386b0..864c23b510c 100644
--- a/src/mongo/shell/shardingtest.js
+++ b/src/mongo/shell/shardingtest.js
@@ -1408,7 +1408,7 @@ var ShardingTest = function(params) {
     const configRS = this.configRS;
     if (_hasNewFeatureCompatibilityVersion() && _isMixedVersionCluster()) {
         function setFeatureCompatibilityVersion() {
-            assert.commandWorked(csrsPrimary.adminCommand({setFeatureCompatibilityVersion: '3.6'}));
+            assert.commandWorked(csrsPrimary.adminCommand({setFeatureCompatibilityVersion: '4.0'}));
 
             // Wait for the new featureCompatibilityVersion to propagate to all nodes in the CSRS
             // to ensure that older versions of mongos can successfully connect.
diff --git a/src/mongo/unittest/unittest.cpp b/src/mongo/unittest/unittest.cpp
index f3388758ba0..a1d6a81bdb3 100644
--- a/src/mongo/unittest/unittest.cpp
+++ b/src/mongo/unittest/unittest.cpp
@@ -184,7 +184,7 @@ void Test::run() {
 // with a meaningful value will trigger failures as of SERVER-32630.
 void Test::setUp() {
     serverGlobalParams.featureCompatibility.setVersion(
-        ServerGlobalParams::FeatureCompatibility::Version::kFullyUpgradedTo40);
+        ServerGlobalParams::FeatureCompatibility::Version::kFullyUpgradedTo42);
 }
 void Test::tearDown() {
     serverGlobalParams.featureCompatibility.reset();
author	Blake Oler <blake.oler@mongodb.com>	2018-06-21 14:55:01 -0400
committer	Blake Oler <blake.oler@mongodb.com>	2018-07-02 10:50:53 -0400
commit	53a34c4f01d6b18df4c4800df9a72b1eff07fb6a (patch)
tree	59dcf1abafee02e14dc8d1d51c43c0965bcaf29d /src/mongo
parent	b3a542545c7367f96d57cab5e89dc389748c0e2c (diff)
download	mongo-53a34c4f01d6b18df4c4800df9a72b1eff07fb6a.tar.gz